1. Technical Field
The present invention relates to analog circuits in general, and in particular to voltage divider circuits. Still more particularly, the present invention relates to a programmable differential active voltage divider circuit.
2. Description of the Prior Art
Within an analog circuit design, there is usually a need for a voltage divider circuit to provide an output voltage that is a prescribed fraction of the voltage of an input source. Voltage divider circuits are typically produced by connecting at least two resistors in series, and the output is at the common connecting point of which part of the voltage applied to the serial resistors. As a rule, one end of the serial resistors is connected to an input signal whilst the other end of the serial resistors is connected to a common ground.
Referring now to the drawings and in particular to FIG. 1, there is depicted a schematic diagram of an analog voltage divider circuit according to the prior art. As shown, a voltage divider circuit 10 includes a transistor 11, a transistor 12, a variable resistor 13, and a variable resistor 14 connected serially between a power supply 15 and a current source 15. In addition, voltage divider circuit 10 includes an input 16 along with a complementary input 17 and an output 18 along with a complementary output 19. In this arrangement, transistors 11 and 12 match with one another in a one-to-one ratio. Similarly, variable resistors 13 and 14 match with one another in a one-to-one ratio. Because of such symmetry, the output voltage appearing at outputs 18, 19 tracks changes in the input voltage at inputs 16, 17.
One problem with voltage divider circuit 10 is its limited bandwidth. Thus, it is desirable to provide an improved voltage divider circuit with a higher bandwidth.
In accordance with a preferred embodiment of the present invention, a voltage divider circuit includes a pair of complementary inputs separated by a common input signal node, a pair of complementary outputs, and a pair of divider circuits coupled between the pair of complementary inputs and the pair of complementary outputs. The pair of divider circuits divide input voltages at the pair of complementary inputs, and produces the divided input voltages appear at the pair of complementary outputs, respectively.
All objects, features, and advantages of the present invention will become apparent in the following detailed written description.